Patients scheduled for carotide endarterectomy under regional anaesthesia (ropivacaine 4.75 mg/ml) are randomised into 2 groups according to the technique of anaesthesia performed: superficial cervical block (Control group) or, ultrasound guided intermediate cervical block (Echo group). Main outcome is cervical block success, defined by surgery performed under regional anaesthesia without supplemental topical lidocaine. Secondary outcomes are rate of conversion to general anaesthesia, total dose of supplemental topical lidocaine and block-related complications.